Question

what do you mean by mitochondria

Answer 1

mitochondria is called power houses of cells.Mitochondria supplies energy which is useful for the function of the cell.It contains enzymes

Answer 2

Mitochondria are small, spherical or cylindrical organelles. Generally a mitochondrian is 2-8 micron long and about 0.5 micron wide. It is about 150 times smaller than the nucleus. There are about 100-150 mitochondria in each cell. When seen under the compound microscope, the mitochondria appear as oval or cylindrical dots in the cell. 
Mitochondria are made up of a double-membrane wall. The inner membrane of the wall protrudes into the interior in folds and forms structures called cristae; the space between cristae is filled with a fluid known as matrix.
Mitochondria is responsible for cellular respiration, a process through which cell derives its energy to do work. Because of this, mitochondria are also known as the powerhouse of the cell.